Acheron is a plane of War. This much is known to any who know the name. But it is not the plane of uncontrolled, unmanaged skirmishes. It is not the plane of revolution or insurgency, of individuals fighting against a grand foe. It is the plane of one military force striking against another; of regimented orders and tactics; of war not between peoples, but between states. The plane of, as Acheronian high-ups often call it, "the Game of War". A game where outside the Rules of War, all is prohibited, but within those Rules, all is not only allowed but expected. Here, war is planned and directed at the scale of squadron against squadron, of regiment against regiment, and of army against army. On Acheron, war is but a game of battlefield strategy, where each warring side fights for the total domination of its opponent.

Acheron stands in opposition to Ysgard; where Ysgard is focused on proving oneself in individual combat, in Acheron the individual is irrelevant. What matters is the goal of the state, and the army is but a set of pieces on a massive game board to achieve that goal, each trusted to perform to the best of their ability, yet none irreplaceable within the ranks. The balance innate to Acheron helps to achieve this; in Acheron, all must be balanced always, for no force is to win through overwhelming or devastating their opponent. Here, war is about force of wits, not force of numbers, and the plane itself demonstrates that: a birth on one side must be balanced by a birth on the other, or else a death alongside. Every new ally manifesting on one side must be matched by an ally for the other, or a departure of same. In the game of war, balance is key, for an unbalanced competition is no competition at all. This, of course, does not apply itself to the matter of war itself: a being killed in fair combat, at any scale, needs no match to balance the scales, after all.

Contents

Physical Conditions

Cubes. Ask any being on the planes about Acheron, and this is the first thing to come to mind, for the plane of Acheron consists of nothing but massive iron cubes (or black frozen disks, in the case of Ocanthus) drifting through a grey, airy void. Some claim that the cubes are but teeth broken from gears of Mechanus, but if true (which is unlikely), it must have happened before all written history, for Acheron's nature has been known for as far as any can recall. Cubes of Acheron have been known to range in size from nearly a half-mile an edge to a mere six feet, and the smaller a cube, the older it appears to be. Some portions of Acheron are thick with the plane's cubes, while others are vast voids with nothing but a single cube visible for miles. Each face of a cube holds its own gravity downwards, towards the cube's center, making traversal over an edge or corner at times a tricky maneuver.

Structures are rare on the cubes of Acheron unless dug into the surface rather than out from it, for when two cubes collide (as happens on regular occasion), such collisions are always face-to-face, crushing everything on both faces that fails to escape within in time while issuing a tremendous echoing thunder throughout Acheron and releasing a bit of heat from within both cubes for miles around that serves to stave off the plane's chill. These collisions are never a surprise, an approaching cube visible for days beforehand, and in their wake they leave the colliding surfaces perfectly flat, even mirror-like, each face marred in the aftermath only by thin fracture lines that spread in perfect right angles to themselves and the cube's edges. Given enough damage, a cube will shatter into smaller cubes, each drifting off on its own through the void.

These cubes are not solid, however; nearly all are riddled with artificial tunnels winding throughout their mass, both to escape the dangers of a collision and to mine the cubes within for raw materials: iron, of course. Within the tunnels, as on the surface, gravity always orients itself towards the surface, and it's within these tunnels that the only native sources of food can be found. For flora, Acheron is limited to two edible crops: the barely-edible cubic black fruits known as provender stones that grow both within tunnels and on the surface, or the humid beds of mushrooms that sustain the thin ecosystems of Acheronian tunnels, supporting what little insect life manages to scrape by. Within or atop the cubes, the only common traditional animals are insects and arachnids; beyond, Acheron is known for its massive flocks of birds flying from cube to cube, feeding on provender stones or insects, or scavenging the dead of Acheron's battlefields. Ravens, crows, gulls, sparrows, pigeons, bloodhawks, vultures, and swallows are all common in Acheron, and almost never found alone; in fact, so rare is it to see a lone bird, to encounter one is considered a horrible omen on the plane.

Of course, Acheron's most well-known native life is the pestilence to all adventurers known as the rust monster. In Acheron can be found the largest population of rust monsters in all reality, and many believe the creature may in fact have originally come from this plane. So common are they that they're often trained as pack animals, able to navigate atop and within the cubes with ease; such a plague are wild rust monsters, however — not to mention their mature forms, rust dragons — that all large communities will keep a store of wooden or stone weapons purely to deal with any passing herds or hungry dragons that might catch the scent of their armories.

The environment of Acheron is livable, but not much more than that. There's always a chill to the plane, and the deeper one travels down its layers, or the further into the emptier regions, the worse the chill gets. The cubes draw heat from the air, a heat that's refreshed and released only by a collision. As a result, the more crowded a region is, the warmer it is, and those lone cubes that manage to keep distant from all others will eventually begin to gather snow; as a result, blizzards are taken as signs of luck in Acheron, as they mean that a cube's managed to escape collision for months upon months. The air is just slightly thinner than most Prime worlds, enough to be noticed but not enough to exhaust a warring army. The gray light of Acheron never grows much brighter than an overcast day, and never dims so much that a person can't see their hand in front of them; normally, it's an ambient glow coming from all about, but in the more crowded regions of the plane the light's broken into shafts and shadows, occasionally glinting off the surface of a recently-collided cube, possibly giving the illusion of a passing star in the sky.

Magical Conditions

By far, the most significant impact in Acheron to spellcasting is the aforementioned need for balance. Every action in Acheron in support of one side must be balanced by an equal reaction elsewhere, whether that be a boon for ones opponents or a bane for oneself. Some spells manifest this more directly than others. For example, positive energy cannot be conjured without also conjuring negative energy in equal amount, unless the conjurer's presence is so great that the conjuration is of no matter to balance.[1]

However, no spell is exempted from this. For each spell cast in Acheron that does not find itself impacted otherwise by the nature of the plane, a special variety of spell crystal (known here as a "spell reflection") forms manifesting the precise opposite effect. Reversible spells create reflections of their opposite, naturally enough; other spells are more obscure. Polymorphing an elf into a snail would generate a reflection to polymorph the impacted target into an elf. Casting a fireball would generate an iceball reflection of precisely equal effect. All such spell reflections shoot off from the caster at the moment of casting, flying in a random direction (though always generally towards a direction with at least a chance at bringing balance) until either impacting something and triggering, or dissipating and manifesting in place. These spell reflections can be captured using the same means as traditional spell crystals, and can either be used as weapons or used to utterly negate the effect of the original spell, if that effect is constant. However, it's nearly impossible to identify what spell a loose spell crystal is from without triggering it yourself. As such, people rarely attempt to capture them unless the original casting was observed.[2]

Abjuration

No change

Conjuration

Creatures conjured in Acheron must obey the letter of any command, regardless of how dangerous or suicidal it may be, though they are by no means bound to follow the spirit.

Conjuration spells with a duration of one hour or greater that summon or call a sentient being must provide another sentient being to trade places with the one to be conjured until the spell expires; this being has none of the usual protections granted to summoned creatures, and any damage or injury inflicted on them while held hostage persists upon their return. The intended victim must either be willing or ordered from a position of legitimate authority; if not, then the caster is taken instead, and the intended victim gains control over the conjured being.

Divination

Divination spells cast within Acheron do not work against any members of any military or paramilitary organization opposed to the caster.

Any divination spells cast on a member of a larger organization which provide general omens of success or failure, such as augury or divination, extend the result of the spell to cover the entire organization regardless of its size; whatever result would have held true for the target otherwise now applies to the entire organization.

Enchantment

No change

Evocation

No change

Illusion

No change

Necromancy

When casting any spell to raise undead, such as create undead, you gain a +3 bonus to your caster level.

Transmutation

No change

Elemental

Any spell with the air descriptor fails to function inside a cube of Acheron. Spells with the fire descriptor cast while on or within a cube also heat a portion of the cube as the heat metal spell; this effect has an area of effect equal to the area of effect of the spell, plus 10 feet per spell level. Spells with the water descriptor, when cast on the surface of a sphere, have only half effect, and rust the cube directly underneath their full area of effect.

Notes

↑Any spell or effect involving the channeling of positive or negative energy will immediately take effect on the caster with the opposing form of energy. For example, if cure light wounds were cast to heal 7 hp of damage, the caster would be struck with 7 points of negative energy damage. If multiple people are affected by a spell or effect, each individual result reflects separately onto the caster. If the caster has more HD than the target, they may make a Will save at DC 15 to prevent this effect.

↑A spell reflection has the same statistics as glass, and triggers when broken. What form the reflection takes can be difficult to determine; use the above examples as a guide. Any given spell reflection in Acheron can maintain itself for one hour per spell level before it naturally shatters. If a spell reflection is detonated in the area of effect of its original spell, that spell's duration immediately ends and all effects of the spell are negated as though it were never cast. Identifying the spell used to generate a spell reflection from the reflection itself should be treated as identifying a magic item with CL 20; on a failure to identify, the spell reflection is misidentified as a random spell of equal spell level.